In the interest of driver comfort within an automotive vehicle, such as a car, it is generally known to provide support to the lumbar region of the back. Lumbar support structures are placed within the lower region of the seat back proximate to where the lumbar region of the driver's back would be located. Lumbar support structures move an area of the seat back forwardly in a direction generally perpendicular to the horizontal surface of the seat back and against the lumbar region of the driver to support the lumbar region. By supporting the lower vertebral structures of the lumbar region, lumbar support structures support the upper back and provide comfort for drivers, particularly long distance drivers.
To move the lumbar support structure to a proper position, the structure is coupled to an actuator which is adjusted by the driver. The operation of the actuator will usually be determined by the construction of the lumbar support structure as well as the range of movement of the structure that is desired. As a result, a large number of actuators are currently utilized for adjusting lumbar support structures.
Several of the existing actuators for lumbar support structures utilize large numbers of complicated machine parts which increase the cost of manufacturing and installing the actuators, as well as their tendency to malfunction. Furthermore, even with such advanced mechanics, adjustment of available lumbar supports is often difficult. Some actuators utilize a handle which is turned by the driver for extending the lumbar support structure. Due to the construction of these lumbar support structures, the handle generally requires a substantial amount of torque in order to accomplish the desired adjustment. The required torque will oftentimes increase as the lumbar support structure is extended further. As may be appreciated, the turning of a handle with high torque would be difficult if not impossible to accomplish when a person is driving. Furthermore, drivers may be too weak to conveniently adjust the lumbar support structures, thus reducing their usefulness.
Motorized actuators are also available wherein the driver presses a series of buttons to actuate motors or air pumps to provide the movement of the lumbar support structure. While motorized actuators eliminate the physical requirements of the driver for providing such adjustment, they are generally expensive to manufacture. Furthermore, they are reliant upon a source of electricity and are subject to electrical failure which may render the lumbar support structure non-adjustable.
Another drawback to some existing lumbar support actuators is that many are not infinitely adjustable. For example, adjustments might be accomplished with a handle and a shaft which has a plurality of detents formed therein. Bearings or other suitable structures move into the detents when the handle is turned and a position is chosen. However, the lumbar support structures cannot be adjusted to positions in between the detents, and therefore, only a limited number of discreet positions of lumbar support are available. As may be appreciated, many drivers will not be comfortable at one of the discreet positions and would be more properly supported by a position somewhere therebetween.
Several available lumbar support structures utilize cables, referred to as bowden cables, to provide the necessary adjustment. In a bowden cable assembly, a wire cable is pulled through a sleeve having a fixed length which is fixed at its ends between two stationary elements. The cable is thus moved, while the sleeve is generally stationary, to effect relative movement of an element coupled to the cable with respect to another element coupled to the sleeve. Bowden cables are inexpensive and flexible and, because of their length, they provide various different positions for placement of an actuator. Thus, it is becoming ever more desirable in the field of lumbar supports to utilize actuators which operate with a bowden cable assembly.
Some attempts have been made to provide an economical manual lumbar support actuator, as evidenced by patents in the field. However, prior art actuators often are expensive to fabricate and difficult to assemble. Their construction requires precise alignment between the parts for coupling the actuator to a bowden cable assembly which slows down the assembly process. Furthermore, their assembly is generally more complicated than is desirable.
Accordingly, it is an objective of the present invention to provide an actuator for a lumbar support structure which is relatively inexpensive to manufacture and install.
It is another objective of the invention to provide easy assembly and operation in a lumbar support actuator.
It is another objective of the present invention to provide an actuator which provides smooth, easy adjustment of the lumbar support structure without a large amount of physical force from a driver.
It is another objective of the present invention to reduce the complication of a lumbar support structure actuator while providing infinite adjustment over the range of adjustment of the lumbar support structure.
It is still a further objective of the invention to actuate a lumbar support structure which meets the above objectives without reliance on a source of electricity and motorized adjustment.